BIOS upgrade Lenovo Flex-14IWL

Earlier this year, I picked up a quad core i5 Lenovo Flex-14IWL with 16G of RAM and loaded it with Pop!_OS.  Everything works great on it except for the fingerprint reader.  I was checking the Lenovo website and discovered that there was a BIOS update available for my laptop.  Unfortunately, the only way to apply the update is to run an application in Windows.  Here's how I got the update done.

Some background

To install Pop!_OS I had to reconfigure the BIOS to disable the Intel RST setting and switch from UEFI boot to Legacy.  Windows 10 and the BIOS updater only run under the UEFI system.

The Windows 10 Install

Having rebuilt quite a few Windows 10 machines I have experience with installing Windows 10 from a USB flash drive.  However, what I was after this time is to install and run Windows from an external drive.  The planned target device was a 500G 7200rpm 2.5" HDD that was put into a USB 3.0 enclosure.  To do this work, I used a Lenovo Thinkpad Yoga S1 running Windows 10.  I was able to follow an article to image Windows 10 using Rufus.   Here is an article that explained how to target an external USB 3.0 HDD with Rufus.  So, key settings were to specify the HDD, use the Windows 10 ISO,  Windows to go installation,  Windows Home selected, and GPT/UEFI format.

Once Rufus finished its work, I copied over the BIOS update file to the external drive.

Windows 10 Install and BIOS update

Get a paper clip.  Bend it open.  With the laptop powered off.  Take the end and insert it in the hole on the right side of the laptop near the power button.  This will give you a menu you can use to get into BIOS settings.  You'll need to switch things back to using UEFI and allow USB boot.  Once that is done, reboot the machine with the external USB HDD plugged in.  It should boot up to Windows 10.  Have fun going through the Windows 10 install.  When drivers finish installing and the machine isn't churning any more, you can go ahead and run the BIOS update you downloaded.  It will first extract the application and then you can run it.  Make sure the laptop is plugged in when you do this.  When it seems like the process is done and you have a black screen, WAIT.  The computer will eventually reboot.  Once, everything has completed you can shut down Windows.  Hold onto the external HDD for possible future updates.

Flipping back

Now, get your paper clip again, disable Intel RST and set to Legacy boot.  Enjoy Linux again.